The present invention is directed to a dry cleaning composition, more specifically, to a siloxane fluid based composition, for use in dry cleaning and to a dry cleaning process using the composition.
Current dry cleaning technology uses perchloroethylene (xe2x80x9cPERCxe2x80x9d) or petroleum-based materials as the cleaning solvent. PERC suffers from toxicity and odor issues. The petroleum-based products are not as effective as PERC in cleaning garments.
Cyclic siloxanes have been reported as spot cleaning solutions, see U.S. Pat. No. 4,685,930, and as dry cleaning fluids in dry cleaning machines, see U.S. Pat. No. 5,942,007. Other patents disclose the use of silicone soaps in petroleum solvents, see JP 09299687, and the use of silicone surfactants in super critical carbon dioxide solutions has been reported, see, for example, U.S. Pat. No. 5,676,705 and Chem. Mark. Rep., Dec. 15, 1997, 252(24), p. 15. Non-volatile silicone oils have also been used as the cleaning solvent requiring removal by a second washing with perfluoroalkane to remove the silicone oil, see JP 06327888.
Numerous other patents have issued in which siloxanes or organomodified silicones have been present as addenda in PERC or petroleum based dry cleaning solvents, see, for example, WO 9401510; U.S. Pat. Nos. 4,911,853; 4,005,231; 4,065,258.
There is a continued interest in providing an additive or additives to enhance the cleaning ability of silicone based dry cleaning solvents.
In a first aspect, the present invention is directed to a dry cleaning composition, comprising a volatile cyclic, linear or branched siloxane and one or more organic surfactants.
In a second aspect, the present invention is directed to a method for dry cleaning an article, comprising contacting the article with a composition comprising a cyclic, linear or branched siloxane and an organic surfactant which may be chosen from the classes of nonionic, cationic, anionic or amphoteric.
The process of the present invention exhibits improved performance, such as for example, removal of water soluble stains from the article, for example a garment, being cleaned. The process of the present invention also effectively removes most soluble stains, including oil stains and grease stains.
In a preferred embodiment, the composition comprises, based on 100 parts by weight (xe2x80x9cpbwxe2x80x9d) of the composition, from greater than 90 pbw to 99.99 pbw, more preferably from 92 pbw to 99.9 pbw and even more preferably from 95 pbw to 99.5 pbw of the siloxane and from 0.001 pbw to less than 10 pbw, more preferably from 0.01 pbw to 8 pbw and even more preferably from 0.1 pbw to 5 pbw of the surfactant. The composition optionally further comprises water, preferably from 0.01 pbw to 15 pbw, more preferably from 0.1 pbw to less than 12 pbw and even more preferably from 0.2 pbw to 10 pbw of water. Preferably, the composition does not include siloxane resins or crosslinking agents.
In a preferred embodiment, the water may be added as xe2x80x9cfreexe2x80x9d water or may be delivered by an emulsion containing other components such as siloxanes, hydrocarbons, surfactants, or other suitable additives. If the water is delivered by an emulsion, the emulsion may be prepared by either homogenization of the components or by mechanically stirring the mixture.
Compounds suitable as the linear or branched, volatile siloxane solvent of the present invention are those containing a polysiloxane structure that includes from 2 to 20 silicon atoms. Preferably, the linear or branched, volatile siloxanes are relatively volatile materials, having, for example, a boiling of below about 300xc2x0 C. point at a pressure of 760 millimeters of mercury (xe2x80x9cmm Hgxe2x80x9d).
In a preferred embodiment, the linear or branched, volatile siloxane comprises one or more compounds of the structural formula (I):
M2+y+2zDxTyQzxe2x80x83xe2x80x83(I)
wherein:
M is R13SiO1/2;
D is R2R3SiO2/2;
T is R4SiO3/2;
and Q is SiO4/2 
R1, R2, R3 and R4 are each independently a monovalent hydrocarbon radical; and
x and y are each integers, wherein 0xe2x89xa6xxe2x89xa610 and 0xe2x89xa6yxe2x89xa610 and 0xe2x89xa6zxe2x89xa610.
Suitable monovalent hydrocarbon groups include acyclic hydrocarbon radicals, monovalent alicyclic hydrocarbon radicals, monovalent and aromatic or fluoro containing hydrocarbon radicals. Preferred monovalent hydrocarbon radicals are monovalent alkyl radicals, monovalent aryl radicals and monovalent aralkyl radicals.
As used herein, the term xe2x80x9c(C1-C6)alkylxe2x80x9d means a linear or branched alkyl group containing from 1 to 6 carbons per group, such as, for example, methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, pentyl, hexyl, preferably methyl.
As used herein, the term xe2x80x9carylxe2x80x9d means a monovalent unsaturated hydrocarbon ring system containing one or more aromatic or fluoro containing rings per group, which may optionally be substituted on the one or more aromatic or fluoro containing rings, preferably with one or more (C1-C6)alkyl groups and which, in the case of two or more rings, may be fused rings, including, for example, phenyl, 2,4,6-trimethylphenyl, 2-isopropylmethylphenyl, 1-pentalenyl, naphthyl, anthryl, preferably phenyl.
As used herein, the term xe2x80x9caralkylxe2x80x9d means an aryl derivative of an alkyl group, preferably a (C2-C6)alkyl group, wherein the alkyl portion of the aryl derivative may, optionally, be interrupted by an oxygen atom, such as, for example, phenylethyl, phenylpropyl, 2-(1-naphthyl)ethyl, preferably phenylpropyl, phenyoxypropyl, biphenyloxypropyl.
In a preferred embodiment, the monovalent hydrocarbon radical is a monovalent (C1-C6)alkyl radical, most preferably, methyl.
In a preferred embodiment, the linear or branched, volatile siloxane comprises one or more of, hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, dodecamethylpentasiloxane, tetradecamethylhexasiloxane or hexadecamethylheptasiloxane or methyltris(trimethylsiloxy)silane. In a more highly preferred embodiment, the linear or branched, volatile siloxane of the present invention comprises octamethyltrisiloxane, decamethyltetrasiloxane, or dodecamethylpentasiloxane or methyltris(trimethylsiloxy)silane. In a highly preferred embodiment, the siloxane component of the composition of the present invention consists essentially of decamethyltetrasiloxane.
Suitable linear or branched volatile siloxanes are made by known methods, such as, for example, hydrolysis and condensation of one or more of tetrachlorosilane, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, or by isolation of the desired fraction of an equilibrate mixture of hexamethyldisiloxane and octamethylcyclotetrasiloxane or the like and are commercially available.
Compounds suitable as the cyclic siloxane component of the present invention are those containing a polysiloxane ring structure that includes from 2 to 20 silicon atoms in the ring. Preferably, the linear, volatile siloxanes and cyclic siloxanes are relatively volatile materials, having, for example, a boiling point of below about 300xc2x0 C. at a pressure of 760 millimeters of mercury (xe2x80x9cmm Hgxe2x80x9d).
In a preferred embodiment, the cyclic siloxane component comprises one or more compounds of the structural formula (II): 
wherein:
R5, R6, R7 and R8 are each independently a monovalent hydrocarbon group; and a and b are each integers wherein 0xe2x89xa6axe2x89xa610 and 0xe2x89xa6bxe2x89xa610, provided that 3xe2x89xa6(a+b)xe2x89xa610.
In a preferred embodiment, the cyclic siloxane comprises one or more of, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, tetradecamethylcycloheptasiloxane. In a more highly preferred embodiment, the cyclic siloxane of the present invention comprises octamethylcyclotetrasiloxane or decamethylcyclopentasiloxane. In a highly preferred embodiment, the cyclic siloxane component of the composition of the present invention consists essentially of decamethylcyclopentasiloxane.
Suitable cyclic siloxanes are made by known methods, such as, for example, hydrolysis and condensation of dimethyldichlorosilane and are commercially available.
The organic surfactant of the present invention comprises one or more surfactants selected from nonionic, cationic, anionic and amphoteric surfactants. In another embodiment, the organic surfactant comprises a mixture of two or more surfactants of the same or different classes, as long as they are compatible, such as, for example, a mixture of two or more nonionic, cationic, anionic or amphoteric surfactants, a mixture of nonionic and cationic surfactants, a mixture of nonionic and anionic surfactants, a mixture of nonionic and amphoteric surfactants, a mixture of cationic and anionic surfactants, a mixture of cationic and amphoteric surfactants, a mixture of anionic and amphoteric surfactants, a mixture of nonionic, cationic and anionic surfactants, a mixture of nonionic, anionic and amphoteric surfactants, a mixture of cationic anionic and amphoteric surfactants, or a mixture of nonionic, cationic, anionic and amphoteric surfactants.
Compounds suitable for use as the nonionic surfactant of the present invention are those that carry no discrete charge when dissolved in aqueous media. Nonionic surfactants are generally known in the art and include, for example, alkanol amides (such as, for example, coco, lauric, oleic and stearic monoethanolamides, diethanolamides and monoisopropanolamides), amine oxides (such as, for example, polyoxyethylene ethanolamides and polyoxyethylene propanolamides), polyalkylene oxide block copolymers (such as, for example, poly(oxyethylene-co-oxypropylene)), ethoxylated alcohols, (such as, for example, isostearyl polyoxyethylene alcohol, lauryl, cetyl, stearyl, oleyl, tridecyl, trimethylnonyl, isodecyl, tridecyl), ethoxylated alkylphenols (such as, for example, nonylphenol), ethoxylated amines and ethoxylated amides, ethoxylated fatty acids, ethoxylated fatty esters and ethoxylated fatty oils (such as, for example, mono- and diesters of acids such as lauric, isostearic, pelargonic, oleic, coco, stearic, and ricinoleic, and oils such as castor oil and tall oil), fatty esters, fluorocarbon containing materials, glycerol esters (such as, for example, glycerol monostearate, glycerol monolaurate, glycerol dilaurate, glycerol monoricinoleate, and glycerol oleate), glycol esters (such as, for example, propylene glycol monostearate, ethylene glycol monostearate, ethylene glycol distearate, diethylene glycol monolaurate, diethylene glycol monolaurate, diethylene glycol monooleate, and diethylene glycol stearate), lanolin-based surfactants, monoglycerides, phosphate esters, polysaccharide ethers, propoxylated fatty acids, propoxylated alcohols, and propoxylated alkylphenols, protein-based organic surfactants, sorbitan-based surfactants (such as, for example, sorbitan oleate, sorbitan monolaurate, and sorbitan palmitate), sucrose esters and glucose esters, and thio- and mercapto-based surfactants.
In a preferred embodiment, one component of the present invention comprises one or more nonionic surfactants according to one or more of the structural formulas III and IV:
xe2x80x83R9xe2x80x94Oxe2x80x94(CH2xe2x80x94CH2xe2x80x94O)nxe2x80x94R10xe2x80x83xe2x80x83(III)
R9xe2x80x94Oxe2x80x94(CH2xe2x80x94C(CH3)Hxe2x80x94O)nxe2x80x94R10xe2x80x83xe2x80x83(IV)
wherein:
R9 is a monovalent hydrocarbon group of 1-30 carbons that may be linear, cyclic, branched, unsaturated, aromatic or fluoro containing, R10 is hydrogen or a monovalent hydrocarbon group of 1 to 30 carbons that may be linear, cyclic, branched, unsaturated, aromatic or fluoro containing, and n is from about 1 to about 100, more preferably from about 1 to about 40. In a highly preferred embodiment, R9 contains from 2 to about 24 carbons, even more preferably from 8 to 24 carbons, R10 is H and n is from about 2 to about 20.
In another preferred embodiment, one component of the present invention comprises one or more nonionic surfactants that may be a sugar-based surfactant according to one or more of the structural formulas V and VI: 
wherein:
each R17, R18, R19, R20, R21, R22, R23, R24 and R25 is independently H or a monovalent hydrocarbon group of 1 to 30 carbons that may be linear, cyclic, branched, an oxygenated alkane or other chalcogen containing group. Chalcogens are herein specifically defined as oxygen, sulfur, selenium, tellurium and polonium. These surfactants may also be the open-chain analogs. In a preferred embodiment, R17, R18, R19, R20, R21, R22, R23, R24 and R25 are each H or a hydrocarbon group of 1 to 24 carbons, preferably a polyether or ester, even more preferably, one of R17 and R20 is a hydrocarbon of from 8 to 24 carbons while the other is H or a hydrocarbon of from 1 to 4 carbons, such as xe2x80x94CH2OH or xe2x80x94CH2CH3, and one of R21 and R25 is H or a hydrocarbon of from 8 to 24 carbons while the other is a hydrocarbon of from 1 to 4 carbons, such as xe2x80x94CH2OH or xe2x80x94CH2CH3. In another preferred embodiment, the surfactant or surfactants are chosen from sucrose esters, glucose esters, monoglycerides, polysaccharide ethers and sorbitan-based surfactants.
In another preferred embodiment, one component of the present invention comprises one or more nonionic surfactants that may be an amine-based or phosphate ester-based surfactant according to one or more of the structural formulas VII and VIII: 
wherein:
each R11, R12, R13, R14, R15, and R16 is independently H or a monovalent hydrocarbon group of 1 to 30 carbons that may be linear, cyclic, branched, unsaturated, aromatic, fluoro containing, an oxygenated alkane or other chalcogen containing group. In a preferred embodiment, two of R11, R12 and R13, are H or hydrocarbon groups of 1 to 4 carbons, and one is a hydrocarbon group of from 8 to 24 carbons, and R14 and R15 are either H or hydrocarbon groups of from 1 to 4 carbons while R16 is a hydrocarbon group of from 8 to 24 carbons, or R14 and R15 are hydrocarbon groups of from 8 to 24 carbons while R16 is a hydrocarbon group of from 1 to 4 carbons. In a most preferred embodiment, the surfactant or surfactants are chosen from alkanol amides, amine oxides, ethoxylated amines, ethoxylated amides and phosphate esters.
Compounds suitable for use as the anionic surfactant of the present invention are those having polar, solubilizing groups such as carboxylate, sulfonate, sulfate and phosphate. Anionic surfactants are generally known in the art and include, for example, alkyl aryl sulfonates (such as, for example, alkylbenzenesulfonates), alkyl aryl sulfonic acids (such as, for example, sodium and ammonium salts of toluene-, xylene- and isopropylbenzenesulfonic acids), sulfonated amines and sulfonated amides (such as, for example, amidosulfonates), carboxylated alcohols and carboxylated alkylphenol ethoxylates, diphenyl sulfonates, fatty esters, isethionates, lignin-based surfactants, olefin sulfonates (such as, for example, RCHxe2x95x90CHSO3Na, where R is C10-C16), phosphorous-based surfactants, protein based surfactants, sarcosine-based surfactants (such as, for example, N-acylsarcosinates such as sodium N-lauroylsarcosinate), sulfates and sulfonates of oils and/or fatty acids, sulfates and sulfonates of ethoxylated alkylphenols, sulfates of alcohols, sulfates of ethoxylated alcohols, sulfates of fatty esters, sulfates of aromatic or fluoro containing compounds, sulfosuccinnamates, sulfosuccinates (such as, for example, diamyl-, dioctyl- and diisobutylsulfosuccinates), taurates, and sulfonic acids.
In a preferred embodiment, one component of the present invention comprises one or more anionic surfactants that may be a sulfosuccinate, sulfate, sulfonate, carboxylate, or phosphorous containing surfactant according to one or more of the structural formulas IX to XIII: 
wherein:
each R26, R27, R28, R29 and R30 is independently a monovalent hydrocarbon group of 1 to 30 carbons that may be linear, cyclic, branched, unsaturated, aromatic, fluoro containing, an oxygenated alkane or other chalcogen containing radical, and X is H or an alkali metal, alkaline earth element or a chalcogen containing counterion or other suitable cation that does not unduly interfere with the functioning of the molecule as a surfactant where the subscript q is the valence or oxidation state of the cation X. In a preferred embodiment, R26 and R27 are linear hydrocarbon groups of from 4 to 20 carbons, more preferably 6 to 13 carbons, R28 is a hydrocarbon group of from 6 to 20 carbons, more preferably from 8 to 16 carbons, and R29 is a hydrocarbon group of from 8 to 26 carbons, more preferably from 10 to 20 carbons, and R30 is a hydrocarbon of from 8 to 30 carbons.
Compounds suitable for use as the cationic surfactant of the present invention are those having a positive charge when dissolved in aqueous media, which resides on an amino or quaternary nitrogen. Cationic surfactants are generally known in the art and include, for example, amine acetates, amines (such as, for example, oxygen-free amines such as monoalkylamines, dialkylamines and N-alkyltrimethylene diamines, and oxygen-containing amines such as amine oxides, ethoxylated alkylamines, 1-(2-hydroxyethyl)-2-imidazolines, and alkoxylates of ethylenediamine), and quaternary ammonium salts (such as, for example, dialkyldimethylammonium salts, alkylbenzyldimethylammonium chlorides, alkyltrimethylammonium salts and alkylpyridium halides), and quaternary ammonium esters (such as, for example, diethyl ester dimethyl ammonium chloride).
In a preferred embodiment, one component of the present invention comprises one or more cationic surfactants that may be a quaternary amine-based surfactant according to the structural formula XIV:
(R31R32R33R34N+)pJxe2x88x92xe2x80x83xe2x80x83(XIV)
wherein:
each R31, R32, R33, and R34 is independently H or a monovalent hydrocarbon group of 1 to 30 carbons that may be linear, cyclic, branched, unsaturated, aromatic, fluoro containing, an oxygenated alkane or other chalcogen containing group, and J is a suitable anion having an oxidation state or valence p that does not unduly interfere with the functioning of the molecule as a surfactant. In a preferred embodiment, R31 and R32 are hydrocarbon groups of from 1 to 4 carbons, more preferably, methyl, and R33 and R34 are hydrocarbon groups of from 6 to 30 carbons, more preferably from 8 to 24 carbons.
Compounds suitable for use as the amphoteric surfactant of the present invention are those containing both an acidic and basic hydrophilic group. Amphoteric surfactants are compatible with anionic and cationic surfactants. Amphoteric surfactants are generally known in the art and include, for example, betaine derivatives such as alkylbetaines and amidopropylbetaines, block copolymers, imidazolines and lecithins.
In a preferred embodiment, one component of the present invention comprises one or more amphoteric surfactants according to the structural formula XV: 
wherein:
each R35, R36 and R37 is independently H or a monovalent hydrocarbon group of 1 to 30 carbons that may be linear, cyclic, branched, unsaturated, aromatic, fluoro containing, an oxygenated alkane or other chalcogen containing group, G is a divalent spacer group, and Y is a carboxylate, sulfonate, sulfate, phosphonate or other similar group. In a preferred embodiment, R35, is a hydrocarbon of from 1 to 4 carbons, and R36 and R37 are hydrocarbons of from 6 to 24 carbons.
Surfactants are known in the art and are commercially available under many trade names from many sources, such as for example, Akzo Chemical Co., Calgene Chemical Inc., Emkay Chemical Co, Hercules, Inc., ICI Americas Inc., Lonza, Inc., Rhone Poulenc, Inc., Union Carbide Corp. and Witco Corp.
In a preferred embodiment, the dry cleaning composition of the present invention further comprises a minor amount, preferably, less than 50 pbw per 100 pbw of the composition, more preferably, less than 10 pbw per 100 pbw of the composition, of one or more non-siloxane fluids. Suitable non-siloxane fluids include aqueous fluids, such as, for example, water, and organic fluids, for example, hydrocarbon fluids and halogenated hydrocarbon fluids.
An article, such as for example, a textile or leather article, typically, a garment, is dry cleaned by contacting the article with the composition of the present invention. In a preferred embodiment, the articles to be cleaned include textiles made from natural fibers, such as for example, cotton, wool, linen and hemp, from synthetic fibers, such as, for example, polyester fibers, polyamide fibers, polypropylene fibers and elastomeric fibers, from blends of natural and synthetic fibers, from natural or synthetic leather or natural or synthetic fur.
The article and dry cleaning composition are then separated, by, for example, one or more of draining and centrifugation. In a preferred embodiment, separation of the article and dry cleaning composition is followed by the application of heat, preferably, heating to a temperature of from 15xc2x0 C. to 120xc2x0 C., preferably from 20xc2x0 C. to 100xc2x0 C., or reduced pressure, preferably, a pressure of from 1 mm Hg to 750 mm Hg, or by application of both heat and reduced pressure, to the article.
Testing for water soluble stain removal was accomplished using fabric swatches supplied by the International Fabricare Institute (xe2x80x9cIFIxe2x80x9d) (Silver Spring, Md.) that contained a water soluble dye. The color change of a swatch of this material was measured by a Minolta CR-300(copyright) Colorimeter using the Hunter Color Number difference calculations. The larger the change in Hunter Color Number (xcex94E), the greater the dye removal and the more efficient the cleaning.
The following examples are to illustrate the invention and are not to be construed as limiting the claims.